This invention is concerned with suction pick-up apparatus for handling electrical or electronic components, for example in a component placement machine. The components may be of a variety of shapes and sizes, for example so-called flat packs, S.O. style transistors, leadless chip carriers, dual in line packages, self-type components and the like, as well as so-called "chips".
In the manufacture of electrical or electronic apparatus it is necessary to assemble a plurality of components on a suitable substrate, for example a printed circuit board. A number of systems have been proposed for handling the components to be placed on a substrate and many of these have proposed the use of pick-up heads preferably using suction to retain a component on a tool of the pick-up head when the component is removed from a suitable component supply means, for delivery to a suitable placement position: see for example our PCT Patent Application Publication No. WO 85/03404. As discussed in this PCT patent application, in order to achieve high productivity it is necessary to handle a variety of sizes and shapes of component in a single machine. As well as handling a wide range of component sizes, apparatus for picking up the components and placing them on substrates must also place them accurately in position on the appropriate substrates at high speed, the components being, in most cases, positioned close to one another on the substrate and the tool should be capable of placing components on a substrate without fouling adjacent components. The machine described by way of example in our aforementioned PCT patent application has proved accurate and efficient in placing components on substrates in accurate locations and in restricted areas. However, in order to accurately position components relative to a pick-up head of this previously known machine so that their position is known for placement, the components are located by means of jaws mounted on the pick-up head to engage the components and move them into a correct orientation, the components being retained on the pick-up head by suction applied through a suitable tool; in order to handle a full range of component sizes, means is provided for exchanging the tools carried by the pick-up head so that the pick-up head presents a tool of a size appropriate to the component to be picked up. Although the machine described by way of example in our aforementioned PCT patent application performed satisfactorily, a restriction is placed on its productivity both by the orienting system which relies on the mechanical jaws (as well as the bulk of the jaws which places a restriction on compactness of the pick-up head: the inertia of the pick-up head mounting the jaws and the necessary operating mechanisms is considerable and therefore restricts the operating speed of the head) and the need to change tools which must be exchanged at a tool holder during the machine cycle and also places a speed restriction on the operation of the machine. Furthermore, although the placement accuracy is high, the use of a purely mechanical orienting system places a restriction on the degree of placement accuracy which can be achieved without resorting to engineering of such a high precision that it becomes prohibitively expensive.
One of the objects of the present invention is to provide an improved suction pick-up apparatus for electrical or electronic components having improved means for providing a number of different pick-up tools.